Note: Variation in leaf shape and indumentum prompted Benoist, R. (1939) recognised 4 varieties in addition to the typical plant, we follow Vollesen, K. (2000) in reducing these to synonymy. Cours 4552 (P) bears a printed label "Itinéraire de Didy à Brickaville", this is assumed to be an error also found in other Acanthaceae species (see Daniel, et al. 2007).